WO2008080670A1 - Method and device for determining an optimized emergency running function in a fault-afflicted engine of a motor vehicle - Google Patents

Abstract

In a motor vehicle which is designed with an emergency running device (N), there is the problem that, in the event of certain fault symptoms occurring, an emergency running function (A,B,C,D) is initiated and the torque of the engine is in the process limited to an unsuitable low value. In the worst case, this can lead to insufficient acceleration of the vehicle being provided for example during an overtaking manoeuvre, and to an accident occurring. According to the invention, it is therefore proposed that the determination of an optimized emergency running function (A,B,C,D) be defined as a function both of the present driving state of the motor vehicle and also of the type of fault symptom. Depending on the fault symptom, the risk (R) and the level of danger (G) are graded into classes and an optimized emergency running function (A,B,C,D) is then determined and initiated. It is thereby advantageously possible to provide sufficient torque and rotational speed to reliably control the vehicle even in an unfavourable traffic situation without damaging the endangered components.

Description

description

Method and device for determining an optimized emergency operation function in a faulty motor of a motor vehicle

The invention relates to a method and a device for determining an optimized emergency program in an afflicted with a fault symptom engine of a motor vehicle according to the preamble of the independent claims 1 and 9. It is already known that motor vehicles equipped in particular with a diesel or gasoline engine are, by law, in a secure mode of operation, ie can continue to operate using an emergency function if a fault symptom has been diagnosed on the engine or one of the vehicle aggregates.

It is further known that the limp-home function is typically implemented in an engine control unit, the engine control unit being specifically designed for optimum engine control in terms of maximum torque, minimum exhaust emissions, and optimum ride comfort. However, a disadvantage is that it, for example when a boost pressure sensor of a turbo engine is defective in a erkann ^¬ th fault symptom and thereby a momentous damage to an affected component may occur in this case, the turbocharger is no hangige the driving condition from ^¬ Notlaufreaktion. In practice, this leads to the fact that limiting the torque, the vehicle can no longer drive through a greater acceleration, which may be necessary especially in a critical driving situation. The lack of acceleration of the motor vehicle can thus lead to a danger of the driver and the vehicle when the driver is suddenly no longer able to adapt the leadership of his motor vehicle to the current traffic situation by limiting the torque. The invention has for its object to provide a method and an apparatus in which or in which the emergency function is optimized and thus improved. This object is achieved with the features of the independent claims 1 and 9.

The erfmdungsgemaßen method or the device has the advantage that when a detected fault symptom on the engine or one of the vehicle devices, the selection and initiation of a limp home not only due to the nature of the detected fault symptom is determined, but taking into account the current driving condition of the motor vehicle. The current driving condition of the motor vehicle is estimated by means of a driving condition estimator based on suitable vehicle and / or engine data transmitted to the driving status viewer. The driving state surveyor determines from the received data a dangerousness (catalytic activity) which represents an instantaneous assessment of the driving state of the motor vehicle. In particular, the Gefahrlich- ness is, for example, a passing maneuver initiated estimated when the torque or the speed of the motor has to be limited at the present time, and thus the maxi ^¬ male torque or the maximum speed grouting no longer hour. Particularly advantageously, that further includes a diagnostic device is provided, which durchfuhrt a classification of the risk for this is that at high torque and high speed of the engine, damage to the Mo ^¬ tor or at a facility could arise also appears. By taking into account the risk of the consequences of Fehlersym- ptoms as well as the hazard of the instantaneous running condition for instantaneous limitation of the torque the initiated emergency operation mode of the motor vehicle is optimized in ^¬ advantageous manner. This can be reduced not only a result of damage to the engine and the vehicle equipment, but also the safety of the driver in flowing ^¬ sequent traffic can be improved. The measures specified in the dependent claims advantageous refinements and improvements of the independent claims 1 and 9 method and the device are given. It is considered particularly advantageous that the optimized emergency function is initiated immediately at the present time. This can be carried out without hesitation in such cases, if the Fahrzustandschatzer classifies the danger of the current driving situation as 'uncritical'. This is for example the case when the vehicle at low speed in

Driving city traffic or the engine is idling. The necessary measures for the emergency function result in this case only from the nature and severity of the error symptom that has occurred.

In the case of a risk with the level "very high" and a danger with the level "non-critical", it is provided that the optimized emergency function is initiated immediately but gradually and / or in the form of a ramp.

If, on the other hand, a 'very critical' classification of the danger was recognized, then it is provided according to the invention that the optimized emergency function is initiated at a later point in time. In particular, it is waited until the danger again reaches the classification 'uncritical' or until a predetermined waiting time has expired.

Another aspect of the invention is that the driver of the motor vehicle is informed by an optical and / or acoustic information and / or warning message on an imminent limitation of the torque or the speed of the motor. By the timely warning message, the driver can choose an appropriate driving style and avoid, for example, a risky overtaking maneuver.

In principle, the classification of both the risk for the individual fault symptoms and the danger of the driving condition in any number of classes can be performed. According to the invention, at least the classes 'very low' and 'very high' or, for the classification of the hazard, the classes "uncritical" and "very critical" may be provided for the classification of the risk.

According to the invention it is furthermore provided that the single ^¬ NEN measures for the optimized emergency operation mode are stored in the form of a program. This makes it possible in an advantageous manner to determine a suitable measure ^¬ acquisition for the limp-home function for different possible combinations of the hazard and the risk immediately.

An embodiment of the invention is illustrated in the schematic drawing and will be explained in more detail in the following description.

Figure 1 shows a schematic representation of a block diagram of an inventive engine with an intake and ei ^¬ nem exhaust tract and

FIG. 2, in conjunction with the tables 1 and 2 depicted in FIG. 3, shows an exemplary embodiment of a flowchart according to the invention with which an optimized emergency operation function can be defined.

1 shows an exemplary embodiment of the invention of an air path 1 of an internal combustion engine with an intake tract Ia and an exhaust tract Ib shown in a schematic representation, which is suitable for an engine, in particular for a diesel turbo engine. The air path 1 has a tubular shape and, in the left part of FIG. 1, has an access opening, through which ambient air is supplied into a combustion space 15 of a cylinder 12 of the engine. The ambient air supplied to the engine has an ambient pressure AMP (Ambient Pressure).

The sucked in ambient air is first filtered via an air filter 2 (AIC, Air Cleaner) and an optional air mass 3 (HFM) and then enters the inlet opening of a compressor 6 (CHA, Charger).

The arrows shown in FIG. 1 indicate the flow direction of the intake ambient air.

The air compressed by the compressor 6 passes via a charge air cooler 7, a throttle valve 10 (THR, Throttle), an intake manifold 11 (IM, intake mamfold) and an intake valve 16 into the combustion chamber 15 of the engine. After the throttle valve 10, a boost pressure sensor 8 is arranged, which continuously detects the boost pressure MAP (M nifold Pressure) and transmits to the program-controlled computing unit 24.

The cylinder 12 has a piston 13, which transmits its oscillating vertical movement to a connecting rod 14, thereby driving a crankshaft. Furthermore, an injection valve 18 is arranged on the cylinder head of the engine, via which the fuel metered into the combustion chamber 15 can be injected.

After the combustion of the fuel-air mixture in the combustion space 15 ^¬ an exhaust valve 17 is opened so that the ent ^¬ avowed exhaust gas is passed through a exhaust manifold 19 in a turbine 21st The turbine 21 includes, for example, adjustable turbine blades that drive the turbine at a high speed. The turbine 21 is mechanically coupled to the compressor 6 and thus drives the compressor 6 depending on the exhaust gas flow. Between the exhaust pipe 19 and the suction pipe 11, a Abgasruckfuhrleitung 22 is arranged, the Durchläse of a Abgasruckfuhrventil AGR is taxable ^¬ erbar. As a result, part of the exhaust gas stream for afterburning can be returned to the combustion chamber 15, thereby improving the exhaust gas emissions.

If, for example, a fault symptom is detected at the boost pressure sensor 8, this can lead to serious consequences for the turbocharger 6, 21 or, depending on the current driving state of the motor vehicle - drove for three Srurity of the motor vehicle, as will be explained later.

As Figure 1 is further removed, a Diagnoseemπch- DE DE, a Fahrzustandsschatzer F and a Notlaufeinrich- device N are provided. The said devices DE, F, N are preferably integrated in the arithmetic unit (engine control unit) 24. Furthermore, a memory 26 is provided, in which the received data can be stored in order to be able to evaluate the time course of the data. The functions of said devices DE, F, N are explained in more detail below with reference to FIG. 2 or Tables 1 and 2 in FIG.

FIG. 2 shows a flow chart for an exemplary embodiment of the invention with which an optimized emergency running function A, B, C, D for operating an engine of a motor vehicle is determined with the aid of an algorithm.

An essential aspect of the invention is that the driving state scout F continuously estimates the current driving state of the motor vehicle, taking into account suitable engine and vehicle data. It is also essential that for the estimated current driving condition of the motor vehicle, a classification of the dangerousness (criticality) in

Classes done. In this case, current values of suitable vehicle data, for example from sensors such as a pedal ^value generator, an acceleration sensor, the vehicle speed, the engine speed, the clutch switch or also information from other control or navigation devices, eg coordinates from the road, from a lane change, steering angle , Vehicle inclination, etc. taken into account. Furthermore, the previous history of the received data is included in order to define the best possible statement about the likelihood of the driving condition. For example, it checks how likely it is that there is an overtaking process right now and how critical it would be if at the moment an immediate limitation of the torque or the speed of the engine was initiated.

The Fahrzustandschatzer F thus provides a weighted information on the danger, if at the present time the limitation of the torque or the speed is ^{¬ initiated} .

Another essential aspect of the invention is that the diagnostic device DE determines a fault symptom on the engine, its facilities or even on the vehicle equipment. For each fault symptom, the risk is assessed that damage may occur at a high torque or high speed of the engine or its inputs. Both the risk of a detected fault and the danger of the driving condition are weighted in several classes and, taking into account the severity, a suitable emergency function A ₇ B ₇ C ₇ D set and initiated, as will be explained in more detail below with reference to the flowchart of Figure 2 ,

First, the flowchart starts at position 30. In positi ^¬ on 31 the driving state estimator F is activated and receives continuously the information provided ergeraten of the engine / vehicle sensors and tax and stores these values, so that the timing of the information can be tracked , In practice, it is envisaged that this process will run continuously.

Furthermore, a diagnostic device DE is activated, which monitors all relevant devices of the engine and the vehicle ^¬ facilities and checks for a possible error symptom. In position 33 is thus continuously queried whether a fault symptom is present or not. If this is not the case, then the program jumps (with n) back to positi ^¬ on 32nd In the other case (at j) a rating of the risk is requested in position 34. The risk classification is carried out from the point of view that at a large torque, in particular at a requested maximum torque ^¬ or a maximum speed of the engine damage to the engine or one of the devices to be considered may arise. The risk assessment is carried out according to the exemplary embodiment in five classes:

a: very low b: low c: medium d: high e: very high

A very low risk (level a) is present, for example, when the indoor air is defective. Such a fault has no effect on a high torque of the engine. In contrast, when the boost pressure plate is not electrically actuated or the turbine blades of the turbocharger are no longer einregelbar, then the probability of Ri ^¬ sikobewertung is very large, that the turbocharger overtightened with a high torque and thus breaks. The turbocharger is a very expensive component, so in this case a corresponding torque limit must be applied to protect the turbocharger. In this case, the risk rating would be 'very high' (e).

According to the flowchart of FIG. 2, a query about the risk classification in steps a to e is thus made in position 35. In position 35, a corresponding classification of the risk is thus determined and stored for each recognized error symptom.

In addition, it is added that there is such a risk classification for every fault symptom.

The number of risk classes can be chosen practically arbitrarily. It is envisaged that at least the class a: "very low" and the class e: "very high" trained because these two classes are easiest to assess in terms of possible damage.

For the driving state fighter F, a similar sequence is provided, as in the case of the diagnostic device DE. In the Fahrzustandschatzer the driving condition of the motor vehicle is estimated from the point of view, which danger arises when, at the present time, a limitation of the torque or speed is initiated. The danger of the driving condition is carried out in position 36. The danger classification of the driving state thus provides information as to whether a limitation of the engine torque at the present time is "uncritical" or, under certain circumstances, "very critical" if, for example, an overtaking procedure has been initiated. The classification of the danger takes place according to the exemplary embodiment in three stages:

a: uncritical b: unknown c: very critical

The classification of the danger is carried out continuously for each driving condition and determined in position 37 a corre ^¬ sponding dangerousness information.

The test for the risk of a detected fault symptom as well as for the interrogation of the Gefahrlichkeitseinstufung refreshes ^¬ economic driving condition takes place temporally in parallel and continuously. On the basis of the determined information in positions 35 and 37, a corresponding emergency function A, B, C, D is determined in position 38, as can be seen from table 2. The determination of the emergency response shall be made in accordance with the class of risk and hazard as shown in Table 1, as explained in more detail below.

In Table 1 of Figure 3 for the risk R, the classes IIa, IIb, Hc, Hd and He are listed in the individual columns. For the dangerousness classes III a, III b and III c entered in the appropriate lines. The functions A, B, C and D are specified in Table 1 as optimized emergency operation functions. Of course, the optimized run-flat functions can be selected as desired and, for example, defined depending on the type of engine or vehicle.

According to the exemplary embodiment, the optimized emergency operation functions A, B, C, D are explained in more detail in Table 2. As can be seen from Table 2, in the case of the optimized emergency function A, the limitation of the torque or the speed of the engine is initiated immediately (not stepped or ramp-shaped).

In the case of the optimized emergency function B, the limitation of the torque or the rotational speed is initiated immediately but executed in a stepwise and / or ramp-shaped manner.

In the optimized emergency function C, the limitation of the torque or the speed is carried out delayed, i. that the limitation of the torque is only initiated when the driving screed F no longer estimates the current driving state as 'unknown' or 'very critically', but as 'non-critical'. The engine control unit 24 must therefore delay the limitation of the torque or the rotational speed until the current driving state permits a limitation of the torque.

In the optimized emergency function D, the procedure is similar to that in the emergency function C. However, in the optimized emergency function D, the delay time is limited to a time maximum value. It is assumed that the limitation of the torque or the rotational speed can not be delayed indefinitely without damaging the engine or one of the vehicle devices.

Table 2 of Fig. 3 further shows in the right column that in addition to the limitation of the torque or the rotational speed is given a visual and / or acoustic Informa ^¬ tion on the limitation of the torque or the speed. In the case A, for example, the information appears on a display: 'limitation of the torque or the rotational speed is active'. In case B the information appears that the, limitation of the torque or the rotational speed is initiated increas ^¬ mend '. When the boundary is initiated, the new information appears that the 'boundary is now active'.

In the case of C, the information or an advance notice appears that the limitation of the torque or the speed, soon initiated. If the limitation has been initiated, then the information appears that the 'limitation is active'.

In the case of D, the information or the notice appears that the, limitation of the torque in the latest xxx seconding ^¬ takes place '. After the limitation has been initiated, the new display then appears that the 'limitation of the torque or the rotational speed is active'.

These displays are updated accordingly ^¬ speaking, depending on the change in the driving situation.

For a better understanding of the invention, the erfmdungsgemaße method will be explained in more detail below with reference to three examples.

In a first example, it is assumed as the starting situation that an electrical fault has been detected between the turbocharger boost pressure regulator and the electronic control unit. This is a serious failure symptom since the turbocharger can be destroyed and high repair costs can occur. The probability that can be damaged or destroyed by ei ^¬ nem high torque of the turbocharger is very high, therefore. The risk R is thus classified as 'very high' according to FIG. 2, position 35. ranks. The result for the risk R is the class He. Thus, the limitation of the torque or the speed should be initiated as soon as possible.

The driving state scout F recognizes, for the instantaneous driving state of the motor vehicle, that the likelihood that an overtaking operation is being initiated at the moment is small, i. a limitation of torque at the present time is 'uncritical'. The classification of the danger G thus takes place in the class IHa (see FIG. 2, position 37).

With the two assessments for the risk R (He) and the danger G (HIa), Table 1 shows the emergency function A according to the column He and the line IHa, ie the limitation of the torque according to Table 2 or the speed can be initiated immediately and without restrictions. Thus, the greatest possible component protection is achieved without endangering the driver, other road users or the motor vehicle. On the other hand it is also ensured that the driver of the vehicle still has the greatest possible torque for the vehicle to continue its disposal until the Def ^¬ ler has been fixed, for example in a workshop.

In a second example, the same fault symptom is assumed, as previously described in the first example WUR ^¬ de. The risk R for a loss thus continues to correspond to the class He ('very high').

However, the driving state scout F recognizes in this case that the probability of a passing process can not be accurately estimated. However, the classification of the danger G now takes place in the class IHb: 'unknown' (see Fig. 2, position 37).

As an optimized emergency function is in this case according to Table 1 from the line IHb and the column He the Emergency running function B found. This means that, according to Table 2, the initiation of the limitation of the torque or the rotational speed is initiated immediately, but in a stepwise and / or ramping manner.

In a third exemplary embodiment, it is assumed that there is a fault of the boost pressure sensor. The risk rating R is assumed to be low for Class IIb (Figure 2, item 35). In this case, the risk for destruction of the turbocharger R ma at ^¬ ximalem torque is relatively low, can be switched to a pilot-operated control charging as technically and thus generally, a sufficient component protection is reached. However, this does not apply if there is a double fault in the system or an extremely unfavorable combination of limit components.

The driving state fighter F estimates the probability that an overtaking operation is being initiated at the moment as 'unknown', so that the class IHb is determined according to position 37 in FIG.

From Table 1, the optimized emergency function C thus results according to line IHb and the column IIb. In the case of the emergency function C, the initiation of the limitation of the torque or the rotational speed is delayed until the driving state scout F indicates 'non-critical' (purple). He also ^¬ follows the notice on the display that, limiting the torque or speed 'will soon be initiated.

If the class (purple) 'uncritical' has been reached, the introduction of the torque or speed limitation takes place and the display shows the new information that the 'limitation of the torque or the speed is active'. Also in this case the vehicle system is usable with maximum availability and controllability. The component protection is clearly subordinated to the driving situation. However, because of the latent danger of the destruction of the turbocharger, the limit according to the emergency function C can not be delayed indefinitely. Therefore erfmdungsgemaß provided that an emergency function D is used when a predetermined waiting time (maximum time limit) has gone from ^¬ . At the same time, on the display for the driver an advance notice is first issued that the "limitation of the torque or the rotational speed m takes place at the latest xxx seconds". If this period of time has expired, then the information appears that the 'limitation of the torque or the rotational speed is active'. The limitation of the torque is in this case with the aim that the vehicle can be operated with its maximum availability in order to avoid accident damage. The component protection is subordinate in this driving situation.

In a further embodiment of the invention, it is provided that the erfmdungsgemaße method for determining an optimized emergency operation for all types of engines, especially for an electrically or gas-powered engine is used.

Claims

claims 1. A method for determining an optimized Notlauffunkti- on for an engine of a motor vehicle, such as a combustion or electric motor, wherein the motor is formed with a device with the on ^{¬ occurrence of} a fault symptom limits the torque and / or the speed of the motor is characterized, characterized in that based on current values of suitable vehicle and / or engine data and / or their previous time course, the current driving condition of the motor vehicle is estimated, - That for the estimated current driving condition of the motor vehicle, a classification of the danger (G) is determined, in particular for the probability that at this time a critical driving condition exists in which a high torque or ei ^¬ ne high speed, for example, required for a pass becomes, - that, for a recognized fault symptom on the engine or on one of the vehicle equipment, a rating for the risk (R) of damaging the engine and / or one of the vehicle equipment at high torque or at high engine speed is assessed, and - that an optimized emergency function (A, B, C, D) is established taking into account the hazard classifications (G) and risk (R) determined. 2. The method according to claim 1, characterized in that the optimized emergency function (A) is initiated immediately when the danger (G) of the driving condition as 'uncritical' (purple) was classified. 3. The method according to claim 2, characterized in that the optimized emergency function (B) is initiated immediately, but stepped or Rampenformig when the risk (R) of the error symptom as 'very high' (He) and the risk friendliness was (G) of the driving state as unknown '(IIIb) a stepped ^¬. 4. The method according to claim 1, characterized in that the optimized emergency function (C, D) is delayed initiated only when the danger (G) Fahrzu ^{¬ the} state of 'unknown' (HIb) or, very critical '(IIIc) back to 'uncritical' (purple) was downgraded (case C) or when a given delay time (case D) has expired. 5. The method according to any one of the preceding claims, characterized in that an optical and / or acoustic information and / or warning message is output to the driver of the motor vehicle, when the torque or the rotational speed of the motor is limited. 6. The method according to any one of the preceding claims, characterized in that for the classification of the risk (R) at least the classes, very low 'and' very high 'are given. 7. The method according to any one of the preceding claims, ^¬ characterized in that for the classification of the danger (G) at least the classes, uncritical 'and, very critical' are given. 8. The method according to any one of the preceding claims, characterized in that measures (A, B, C, D) for the optimized emergency function (N) m are stored in the form of a program. 9. A device for determining an optimized emergency function for an engine of a motor vehicle for a method according to any one of the preceding claims, characterized - That the motor vehicle or the engine is a Fahrzustandsschatzer (F), a diagnostic device (DE) and an emergency running device (N), wherein with the aid of the diagnostic device (DE) a classification for the Ri ^¬ siko (R) of a detected fault symptom and with the help of the driving state estimator (F) a classification for the dangerousness (G) of the driving state of Motor vehicle is carried out, and - That the emergency running device (N) is formed with an algorithm with which an optimized emergency running function (N) can be determined from the classifications for the risk (R) and the danger (G). 10. The device according to claim 9, characterized in that the optimized emergency function (A, B, C, D) is stored in the form of a program. 11. The device according to claim 9 or 10, characterized in that the driving state estimator (F), the diagnostic device (DE) and / or the emergency running device (N) in an engine control unit (24) are integrated.